High-tension switch plant



Feb. 2, 1932. BARTHELT 1,843,659

EIGH TENSION SWITCH PLANT Filed March 5, 1928.

, ATTORNEY Patented Feb. 2, 1932 UNITEDTSTATES- PATENT OFFICE HANS BARTH'ELT, OF BEB-LIN-WILMERSDORF, GERIwIANY, ASSIGNORTO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, OF NEW YORK, N. Y., A CORPORATION HIGH-TENSION swrrcn PLANT Application filed March 3, 1928, Serial no. 258,806, and in Germany March 5, 1927.

My invention relates to a high-tension switchplant.

Theemployment of high voltages (over 100 kv.) for the transmission of electric power over long distances increased naturally the dimensions of the necessary switchgear, since, as well known, the required flash-over distances between live parts and to ground increase rapidly with increasing voltages. The buildings in which such switchgear is accommodated thus attain sizes which demand very large 'floor spaces and this increases the first cost of the plant considerably. In order to reduce the cost of such'switch-houses, it has been'suggested to construct such switchplants as outdoor stations i. e. to mount the switchgear in the open air without enclosing walls. The ground area and space requirement of such a switchplant is, however, not reduced, because the switching equipment is exposed to rain and snow and it is-necessary to locate the individual parts at considerably greater distances apart than in a closed building, if the same flash-over safety is to be maintained. Such outdoor plants thus demand a still larger ground area, than the switchgear located in closed rooms. Such large ground spaces are frequently not available, for instance in the case of the switchplant of waterpower stationserected in mountainous country, or can only be acquired at great cost in large cities at the other end of a long distance transmissionline. Forthis reason it has already been proposed to place switchplants, such as sub-stations, underground under streets and roads.

According to my invention the ground area and cubic space demand of a high-tension switchplant may be considerably reduced by 40 placing the entire switchgear or switching equipment (busbars, disconnecting switches, transformers, oil circuit breakers, current and potential transformers) into an oiltight vessel or vessels constructed of concrete and filled with oil. In this wa the distances necessary between the indivi ual parts of the switchgear may be considerably reduced and the plant be made more compact. The costs for constructing such vessels or tanks of concrete are lovy compared with other structures for housing switchgear, since the concrete ves sels or tanks may be produced directly in the ground by casting the concrete in a manner well known in the art and the constituents of the switchgear may be conveniently mounted on the concrete walls.

It is already known to construct the oil tanks of oil circuit-breakers of concrete, the underlying idea being to obtain a rugged tank capable of withstanding the pressure developed in the event of an explosion within the breaker. This is therefore merely a measure to increase the strength of an oil tank. T0 render the porous concrete impervious to oil it has also been proposed to cover it with a coat of oilproof paint or to provide it with a suitable protective lining.

The object of my invention is primarily to reduce the ground area and cubic space requirement of the total switchplant to make the plant more compact and thus to efi'ect a considerable saving in ground space.

Inapreferred embodiment of my invention the vessel constructed of concrete serving for the reception of the entire switchplant or a plurality of such vessels containing the individual systems of the switchplant is or are subdivided into separate compartments or chambers by insulating partition walls. For the subdivision the same viewpoints are decisive as for the high-tension switchplants in air, such as separating the phases. The insulating partition walls subdividing the entire switchplant into individual compartments are so placed, that they are located behind the'disconnecting switches or isolating links branching the individual systems 011? the ,busbars or the incoming cables from the generator, so that the switchgear located in the individual compartments isdead When the disconnecting switch is open. This is of particular advantage when repairs have to be made onindividual switchgear.

The partition walls are preferably constructed in the manner of bulkheads, well known in the art of ship-buiiding, so that the oil is able to circulate normally through all the chambers, but can be drained out of any individual chamber when the bulkheads are closed, so that any individual chamber may 100 be isolated for repairing the switchgear contained in it. For this purpose auxiliary vessels or receptacles are provided in the vicinity of or adjacent to the concrete mam vessels, which are in communication with the main oil vessels by pipes. Theoil is drawn into these auxiliary, vessels when a. compartment of the main vessel is drained and forced back again when the compartmentisto be filledagain with oil; This ar-- rangement has the advantage that the-compartment in which the switchgear iscon: tained need not be equipped with such pressure or suction apparatus and theparts of-the switching installation are kept free from strains connectedtherewith.

To'preventza switch compartmentrfrom beeing drained. while: carry-ing current; a stop, valve is;v provided in; the. connecting pipe. of.

the main vessel with/the auxiliariy'vesselaor at:

the vessels themselves. This; valve'is. fur;- nished with.- an interlocking mechanism which allows of it. being opened onlyxwhen. thedisoonnectingswitch for the particulan compartment at; the busbarshas been opened;

In order that; the. complete switching iii-- stallation may permanently. be kept. immersed intheoil, provisionsmay be made that the oillevel is continuouslyorperiodically controlled and automatically broughtto'the prescribed height by an oil a pump, should; it. have dropped.

It'is awell knownfact', thati insulating oil greedilyabsorbs moisture from-the; air, par-- ticularly. when the oil level presents'aalarge surface to the air. This absorption OfIHOlS-- ture reduces the dielectric strength a of. the-oil? very rapidly. and must therefore. -be:-prevented as=faraspossibler I avoid the absorption by covering the entire switching installation; or the individual switchingcompartments,v these. enclosures being along their edges; sealedtagainst' the entrance of: air byv troughs containing a liquidinto i-which the edges ip.-.

, These I covers Y may. be designed as-rollerxtops andibelow them there maybe providedaweb of: fine-meshed. wire gauze, which: when; the. covers: are. opened prevent solid; particles from dropping into the insulating; oil These covers may in knownmannerbe. so in? terloeked that they can beopenedonly when; the. switchgear contained in the respective: compartment is dead.

In orderytoenable the insulating oil to be: purified-andto keep its-dielectric properties underg constant supervision, means may be; provided to circulatethe oilfromthe compartments by a system of pipesto apurify-ing plant, whereit is purified'and returned to the switch compartments.

I The switchplan'ti is constructed in the usual; manner, so that. any. portion of: the gear is.- accessible after the draining of the oil for repairs, for instance froma stage. Theoil circuit breakersexisting in the usual installation are, with their usual metal tanks, placed into the oil in order to prevent the pressures developed in such breakers, when opening, from being transmitted to the other parts of: the switchgear. If such a pressure limitation is considered unnecessary, the .oilicircuitbreakers'may. be placed-into the concrete vessels without metal containers, for instance, by placingthem on the bottom of the vessel wherethe highest pressure" prevails: The

transformers, current and potential transformers, extinguisher coils and other oil-filled apparatus also require no longer metal enclosures. My improveddesign of switch station thus does away with all oil containers and: the leading in and out; bushings and consequently also with their oil ciroulating: apparatus. The;v apparatus is; conneetedi up by. meansof. simpleterminals.

A travelling cranetor-hoisting the*-vari-- ous'parts-gof theswitch gean out ofi'the oil'. vessel may beprovidedabove the entire switch: plant and a light roof: may COVGP'lIllB: entire station; The. incoming and outgoing-cables: pass through; suitable bushings-into :the sunroundinggatmospherer.

The drawing. afiixed hereto and; forming part: of my; specification r is: a1 verticali section. and illustrates diagrammatically a; hightension; switching: installation according. to; my invention.

Referring to; the=single figure of the draw?- ing, 1: is :the; underground vessel, tank, .reser voir, cistern .orpit 'constructediofrconcrete and; subdivided into: separate compartments byu insulating; partition. walls; 2; In the 0mm partments; there. are, .fon instance, located? the oil circuit-breakers 3 and'zabove' themupon special horizontal partition walls As the disconnecting switches 5- placed between the bushbarszG and: the oil. cireuitabreakers. 3; The insulating: partition; walls; 2.- and? 4' are preferably. designed; as bulkheads; as: cue;- tomary in;ship-building, so that :undennopmal conditionsltheioil issableto itraverse alll the compartments, but' after: closing theopen 4 ings'7; by the slidingdoors: 8-'eaoh. compartrment may be; drainedseparately and; without affecting the others... In the immediatevicinity oftheroncrete-tank there are pro vided auxiliary vessels 9, one;- ofi whichv is: shown, which-communicate with the concrete vessels-or tanks byrpipes lOa- Initheoonneotting pipes lO 'betrweenethemain eandauxiliaa'yv vessels. there are interposed: stopivalves 11: provided: with locking devices-:which permit: the openingiofsthe stop valves 11 only, when: the disconnecting; switches: or isolating Jinks: 5 are openi and: the switchgear appertaining to themi'stherefore dead. A pump lgf'driven bya motor 20 isprovidedfor each=conduit210 whereby the oilwithin thevariouseoompart ments may be pumpedtherefronrinto it'sre spective auxiliary vessel and whereby the oil' level in each compartment may be controlled.-

III

To prevent the oil from absorbing moisture from the air, the concrete tanks are, for instance, closed by a roller top 12 against contact with the air. These roller tops seal the tank against the entrance of air by dipping with their edges into troughs or gutters 13 filled with a liquid. Foreign substances are prevented from falling into the tank by a fine mesh wire screen 18 supported on the walls and vertical partitions of the tank. The whole switch station is swept by a travelling and elevating crane 14 for hoisting the individual apparatus out of the tank. A light roof structure 15 covers the entire switching installation. 16 are the incoming and outgoing cables of the switchplant which pass through the bushings 17 and are connected to the overhead transmission line.

Various modifications and changes may be made without departing from the spirit and the scope of the invention, and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art.

I claim as my invention:

1. High-tension switch plant comprising a circuit breaker and a disconnecting switch located completely in an underground concrete oiltight vessel filled with oil and subdivided into individual compartments by horizontal insulating partition walls, said partition walls being disposed between the disconnecting switch and the circuit breaker.

2. A high-tension switch plant located completely in an underground oil-tight concrete vessel filled with oil and subdivided into individual compartments b vertical bulkheads and by horizontal bul -heads whereby the apparatus in the lower part of the vessel is isolated from the apparatus in the upper part of the vessel, the said bulk-heads having manholes establishing communication between neighboring compartments and covers for the manholes closing communication between the said compartments.

In testimony whereof, I have hereunto subscribed my name this tenth day of February, 1928, at Berlin-Siemensstadt, Germany.

HANS BARTHELT. 

